Toward Quantification of Ion Exchange in a Sandstone Aquifer
Ion exchange is a very important process in determining the migration of a number of solutes, including pollutants, through aquifer systems. This chapter outlines three studies that aimed at quantifying the ion exchange behavior of the English Triassic sandstones, a fluviatile/Aeolian red-bed sequence whose main exchange phases are clay minerals. The first study described undertook laboratory determination of ion exchange parameters for sandstone samples from northwest England. A second study examined the exchange behavior of sandstone samples in detail, and this resulted in a new empirical description of exchange for the sandstones. A third study attempted to determine how the various exchange phases contribute to the overall exchange behavior of the rock, and hence whether knowledge of the mineralogy of the sandstones can enable exchange properties to be predicted. Ion exchange is directly involved with attenuating a number of pollutant species.